1. Field of the Invention
The present invention generally relates to semiconductor display devices and, more particularly, is directed to a semiconductor display device which can effect color display by energizing self luminous elements of three primary color lights, i.e., red (R), green (G) and blue (B) lights.
2. Description of the Related Art
A red light emitting element is fabricated by epitaxially growing elements of III-V group on a GaAs substrate. Further, there has been proposed a method for fabricating a matrix of red light emitting elements by arranging a plurality of red light emitting elements on the same substrate.
It has been demanded to further form, in addition to the red light emitting element, blue and green light emitting elements on the same substrate to obtain a three primary color light emitting element. However, with regard to light emission at room temperature, even when AlGaInP capable of emitting a light with a shortest wavelength is used, it can emit only a red light. A boron nitride (BN)-based compound semiconductor can emit a blue light. However, the BN-based compound semiconductor cannot have the same lattice constant as that of a GaAs or GaP substrate which is inexpensive and excellent in crystallinity and productivity and also easily available. Therefore, it has been difficult to fabricate a three primary color light emitting element by III-V group elements on the same substrate with a good productivity.
Meanwhile, when a II-VI group element is epitaxially grown on a GaAs substrate, a light emitting diode (LED) or laser diode (LD) capable of emitting a green light can be fabricated. The LED or LD made of the II-VI group element has a structure wherein, for example, a (Cd.sub.0.2 Zn.sub.0.8) Se layer is sandwiched between ZnSe layers.
The assignee of the present application has previously proposed in Japanese Patent Application No. 4-32253 or the like an LD or LED capable of emitting a blue light in which a ZnSe layer is sandwiched between ZnMgSSe layers.
A display device has been reported in which elements are arranged in a juxtaposition fashion. However, this display device has a one pixel size as relatively large as about 5 mm and thus has an entire display region as large as 10 inches or more. Thus, there have neither been suggested yet a display device wherein three primary color light emitting elements are formed on the same substrate nor a method for fabricating the display device.